About this previous year paper
This document contains the complete B.Tech (Semester IV) Theory Examination 2024–25 question paper for Applied Thermodynamics (BME401). The paper consists of two printed pages, carries 70 marks, and evaluates a student’s understanding of thermodynamic cycles, steam power plants, IC engines, turbines, nozzles, combustion, gas turbine cycles, boilers, condensers, and jet propulsion systems.
Section A – Short Theoretical Questions (14 Marks)
Section A contains seven 2-mark questions, each targeting fundamental thermodynamic concepts (Page 1):
Otto vs. Diesel cycle differences
Effect of superheating on Rankine cycle efficiency
Definitions of HHV (Higher Heating Value) & LHV (Lower Heating Value)
Two boiler mountings & two boiler accessories
Meaning of choked flow in nozzles
Impulse vs. Reaction turbines
Advantages of regenerator in gas turbine cycle
These short questions test conceptual clarity on cycles, steam systems, and turbine principles.
Section B – Numerical & Descriptive Questions (21 Marks)
Students must attempt any three out of the five questions.
Rope Brake Dynamometer (IC Engine Performance)
Given pulley diameter, rope diameter, brake load, fuel consumption & calorific value — calculate:
Brake Specific Fuel Consumption (BSFC)
Brake Thermal Efficiency
Ideal Steam Turbine Cycle
Steam expands from 20 bar, 360°C to 0.08 bar, followed by condensation → pump → boiler.
Calculate:
Net work per kg of steam
Cycle efficiency (ideal Rankine cycle)
Surface Condenser
Explanation with neat diagram + effect of air leakage on condenser vacuum & efficiency.
Convergent Nozzle
Derivation of maximum mass flow rate per unit area + definition of nozzle efficiency.
Turbojet Engine
Working with a neat labeled diagram.
These questions check analytical ability, numerical application & thermodynamic reasoning.
Section C – Long, Higher-Order Questions (35 Marks)
Attempts are made one part from each question (Q3–Q7). These questions require deeper understanding, derivations, or complex numericals.
Q3 – Diesel Cycle Efficiency / Turbocharger
Given compression ratio r = 16 and cut-off ratio ρ = 2.5, calculate thermal efficiency of Diesel cycle
OR
Explain turbocharger with diagram and differentiate it from supercharger.
Q4 – Combustion of Alcohol / Flame Temperature
For C₂H₆O, compute:
Stoichiometric air–fuel ratio
Composition of combustion products per kg of fuel
OR
Derive expression for adiabatic flame temperature at constant pressure.
Q5 – Boiler Draught / Boiler Components
Given chimney height (30 m), draught required (12 mm WC), ambient temperature (27°C), air requirement (20 kg/kg fuel) — determine minimum exit gas temperature
OR
Working of feed water heater & superheater and impact on boiler efficiency.
Q6 – Impulse Turbine Velocity Diagram / Turbine Numerical
Draw velocity diagram for single stage impulse turbine and derive:
Work done
Blade efficiency
OR
Numerical involving nozzle efficiency, velocity coefficients, blade speed ratio, blade angles, power developed, thrust, etc.
Q7 – Brayton Cycle / Turboprop Engine
Air enters compressor at 101.325 kPa, 27°C, pressure ratio = 6, WT = 2.5 WC → calculate:
Maximum temperature in cycle
Cycle efficiency
OR
Working of turboprop engine with diagram + difference from turbojet.
Summary
The Applied Thermodynamics (BME401) exam paper covers:
Otto, Diesel, Rankine & Brayton cycles
Superheating, regeneration & turbine expansion
IC engine performance (BSFC, efficiency)
Steam turbines & condensers
Boilers, mountings, accessories & draught
Nozzles & choked flow
Turbojet, turboprop, turbocharger & supercharger systems
Combustion calculations
Velocity diagrams & turbine performance
Gas turbine cycle analysis
This exam paper is a complete resource for mechanical engineering students studying the conversion of heat into work and the performance of power-producing devices.